One form of implant is the root-form dental implant which is placed in extraction site cavities or drilled holes in the mandible or maxillae to support one or more tooth-shaped prosthesis. The root-form implant generally has a cylindrical outer surface to engage bone. While such dental implants may be provided in a limited number of different lengths and diameters, these sizes may not match the exact size needed to sufficiently fill an extraction site to provide prosthesis with proper structural support and proper aesthetic appearance. This is particularly true if the extraction site is an irregular shape or is in an area where there is a ridge defect.
Another form of dental implant is the plate-form or blade-form implant which has a flat plate as the anchor to be placed in the mandible or maxillae, and typically has posts to support one or more prosthetic teeth or crowns either individually or structurally interconnected by a bridge. A plate-form implant may be more stable than a root-form implant in areas where multiple teeth are missing, facial-lingual bone width is small and/or alveolar ridge height is limited. The location of the posts on the implant, however, is preset and may not correspond with the optimal location of the crowns (or bridge) on the jaw. Special allowances then need to be made in the crowns or bridge to account for this which may result in aesthetic compromises. Also, the flat area of the plate faces facially and lingually and is manually bent at the time of surgery to conform to the curvature of the jaw. This procedure is inexact and may damage the implant. A non-fitting curvature of the plate may also cause gaps between the plate and adjacent bone that could compromise healing or may require further time consuming shaping of the bone.
Furthermore, the blade-form implant has been known to promote fibro-osseous integration as opposed to osseointegration. Osseointegration is defined as a direct connection between the implant and viable bone that results in a very immobile implant. In fibrous integration, the implant is surrounded by a membrane like layer of less mineralized tissue that does not hold the implant as well as bone tissue. While fibrous tissue connection may be beneficial because it stimulates the periodontal ligament which cushions the implant from occlusal loads, some degree of osseointegration must occur to provide adequate support to the implant. A total fibrous encapsulation of the implant isolates the implant mechanically from the viable bone of the jaw and endangers the long term survival of the implant.
Yet another form of implant is a bone graft. Sometimes it may be necessary to perform some type of a bone restoring process before a tooth implant can be placed. For instance, if the patient has poor dental health and the patient has been wearing non-implant supported dentures for many years, defects or holes may exist in the bone. The best treatment option in such cases is to repair the bone defects. Larger bone defects are currently treated by harvesting the patients own bone or by using specially treated cadaver bone. The bone harvesting surgery, however, can be more invasive then the bone grafting surgery and adds to the patients discomfort and healing time. Also, whether harvested or cadaver bone is used, the surgeon must shape these bone pieces by hand at the time of surgery to fit the defect. Hand shaping is not exact and gaps between the graft and defect (i.e., bone surface) may compromise healing. Finally, even if an implant customization process could be used, it would be difficult to pre-shape natural bone using automated machining processes without damaging the bone.
Thus, an endosseous implant made of a material that is easily shaped yet provides strong and rapid osseointegration is desired.